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LEC 7 Heart & Vessels.pdf

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Health Sciences
Health Sciences 2300A/B
Jamie Melling

LEC 7: Heart & Vessels September-08-12 1:03 PM • Cardiac muscle • Understand the valve and arteries around the heart in the labs • Unique organ because its constantly active and beating • Works in isolation, when outside factors hinder its ability to function properly- cardiovascular problems being to occur • Heart will beat on its own, as long as its provided with oxygen and nutrients it needs it will beat forever • Hinder return of blood to the heart begin to disorganize return of blood back to heart, heart strivesto overcome this by becoming larger and be more forceful- imbalance occurs prior to heart attack • Engine of the body- runs body and when it starts to decrease in trouble • Heart lies anterior within thoracic cage • Apex - points downwards and at an oblique angle • Sits in a sac- "pericardial sac" • Heart constantly beats within the sac and rubbing against structurescausing friction around the heart that you do not want (inflammatory response) • Sac filledwith fluid to rescue friction - function of the sac to decrease friction • Sac helps anchor heart into position, attached to great vessels run to and from the heart and the diaphragm • b/c thoracic 3/4 lies sternal angle at level of top of heart , T9 bottom of the heart happens at Xiphisternal angle - heart is just behind sternum • Xiphisternal angle - bend or break potential to injure or puncture the heart • 3 functions of the heart • Heart is a pressure generating system, blood will follow across concentration gradients • Left right side to vascular network - general scheme not that simple within body - RIGHT LEFT understand two system come together as one- deoxygenated and oxygenated blood • Deoxy- blue, right and oxy- red- left • Blood within a vein is not blue- blue comes from syinosisa lack of blood , joined the idea of lack of blood to deoxygenated blood ○ Veins are never within blood, not what gives them blue appearance, contain 70% blood at one time in body • Deoxygenated blood is dark red and oxygenated blood is slightly light colour • Veins are transparent, you can see blood through wall of vein, why it has a dark blue appearance (superficial presentation) • Cannot see through arteries because they are thick walled • Deoxygenated blood just has slightly less oxygen in it because it has been utilized - never completely without oxygen in the blood • Once blood is re-oxygenated at lung level, high concentration of O being brought back to heart • CO2 bi-product of oxygen, continuous production which hinders ability of red blood cells to hold oxygen, it is taken out of the body at the lungs - exchange of gasses - pulmonary circuit-CO2 never completely removed • Systemic circuit-all organ systems of body excluding lungs/ heart (11-2= 9) provided blood by the systemic circuit • Coronary system- the hearts ability to provide blood to itself • Artery and vein (red-blue) - cannot identify something as a vein because its blue ○ Vein- returningblood, artery- moving blood away • Pulmonary artery is blue, pulmonary vein is red - do not look at colours flipped • Exchange of gasses, rightside of heart responsible • Blood will travel from concentration gradients - studying pressure receive sense of how it moves • Lung pressure- 15mm of mercury , systemic system - 90 - lower pressure system in lungs ○ Pressure moved from heart- lungs Lectures Page 1 • Pulmonary artery is blue, pulmonary vein is red - do not look at colours flipped • Exchange of gasses, right side of heart responsible • Blood will travel from concentration gradients - studying pressure receive sense of how it moves • Lung pressure- 15mm of mercury , systemic system - 90 - lower pressure system in lungs ○ Pressure moved from heart- lungs • Requires heat to send blood to entire periphery minus lungs heart • Pressure in this circuit around 90, changing on the state of the person • Heart must reach level before blood can be expelled into the systemic circuit - left side of the heart which is much larger and stronger in order to generate this pressure • Circuit within walls of the heart that provides blood to the heart • Rely on thickness of vessels to determine which vessels it is Lectures Page 2 • Rely on thickness of vessels to determine which vessels it is • Aorta- great artery leaving the heart, very thick and provides blood to systemic circuit ○ Arches over the pulmonary artery , branches downwards behind the heart- descending aorta • Pulmonary Artery - brings deoxygenated blood away from the heart to the right side to the lungs to become oxygenated ○ Blue and thin walled • Superior Vena Cava- vein on the superior portion od the heart where it enters • Inferior Vena Cava- collects blood from lower half of the heart ○ Both apart of the systemic circuit ○ Borders these two veins is the diaphragm all blood collected above goes through superior and below inferior • Pulmonary Veins - red and oxygenated ○ Bring blood back to heart from the lungs ○ Two on each side, vary depending on how you pull heart out of section - medially only one pulmonary vein • Coronary Arteries-vessels surrounding heart that move and return blood back to the heart • All stemming into and from the top portion of the heart • Everythingis returningand leaving heart from top half of heart • Aorta is VERY thick walled b/c deals with great amount of pressure from right side of the heart first exposed to aorta which must be strong • Pulmonary artery- brings blood away from heart to pulmonary system 15mm mercury, thin walls, remove heart with no blood insidethe veins will collapse upon themselves • Superior Vena Cava- returns blood from structures above diaphragm • Inferior - • Pulmonary Veins- two on each side, potential to see two on each side • Apex of Heart- peak at bottom, does not necessarily point upwards • Veins given very simplenames- greater cardiac vein and lesser cardiac vein that accompanies cardiac artery's- just need to know where the flow into • Cardiac sinus- thicken vessel all veins of heart pool blood back to the sinus which empties into the right atrium ○ Blood diverted through coronary arteries and pocketed on aortic valve return blood to sinus a pooling station that enters blood back to right side of heart and right ventricleto lungs for re-oxygenation ○ Veins that pool blood back to right atria - superior/inferior cava and coronary sinus • Atria- receiving stations, receive blood from the lungs or periphery system • Ventricles- pumping stations, pump blood out to lungs or systemic circulation • Valves control the amount of blood that moves into each chamber- area that holds blood changes which changes volume • 4 Valves ○ 2 AV valves- right and left, separate atria from ventricles ○ Right side AV valve called tricuspidvalve because it has 3 "cusps", left side AV valve called Bicuspid only has 2 "cusps" don’t know why it has only 2, some argue fewer valves easier it is to control, left generates s much pressure imp to control valves properly ○ Bicuspid valve also called Mitral Valve- based on bishops hat ○ Semilunar Valves- half moon shaped (aortic or pulmonary valve) names originates from where the blood moves to next  Right ventricle- pulmonary system (lungs) • Best to see these valves by removing atria Lectures Page 3 • Best to see these valves by removing atria • Blood is brought to the right atrium then into the right ventricle • When right ventriclepumps blood it passes through pulmonary valve (black) also has 3 semilunar valves • Green - rightventricular valve • Pulmonary artery (blood away from heart to left or right lung) Posterior • Blood moves back into heart and placed into left atria into the left ventricleto be pumped into systemic circulation Left AV • Blood pumped through aortic valve to get into aorta then transferred else where in the body Right AV • Pulmonary valve most anterior Aortic valve Other Internal Structures 1. Chordae tendineae- maintain structureinside heart "heart strings"allows you to generate Pul valve pressure needed to expel blood out 2. Papillary Muscles- small muscles that contract to hold tight heart strings 3. Trabeculae Carnae- " web like"seen in both chambers, difference between papillary is projection off a wall, only a papillary muscle attaches to chordae tendineae • Both papillary muscles and carnae are both muscles that contract similar SUPERIOR VIEW 4. Septum- separates left and right side of the heart that can separate left and right atria an left/rightventricleessentially a "wall" • Ability to generate pressure necessary to expel blood to where it needs to go • Blood moves and shifts, blood moves into right atria it also moves it left atria- organized movement where it moves and shifts • Blood moves out of right ventricleto lungs also left ventricleto systemic system • Right AV closes so does the left- two systems work in sync, not quite matched • Look at either ventricle- same system working , left ventriclegenerates the most pressure to expel blood into aorta and systemic system • Left AV Valve ○ Blood returns from the lungs its fully oxygenated and returns to left atria (no valve controllinglungs-atria moves on easy pressure grade) ○ AV valve opens, blood enters atria slows into left ventricle
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